Currently there exists no technology for routine measurement of cardiac output (CO) in neonates (0.4-2.5Kg) and low weight pediatric (2.5Kg+) patients in the intensive care unit (ICU). Accurate measurement of CO would allow for better assessment of therapies and thereby improve patient health care. Conventional methods used with adults for routine CO measurement are not suitable to be used with the subject population due to small sized vessels in these patients besides procedural complexities. Thus, overall objective of this project is to implement FDA recommendations into the First Minimally Invasive Cardiac Monitor for routine use with the neonatal and low weight pediatric ICU population, using extant catheters in ICU patients. This approach, which is based on the well-established indicator dilution principles, has several advantages including: needs no additional invasiveness, independent of patient size, uses innocuous isotonic saline as indicator, no contact with patients blood, needs less than 5 minutes to establish the set up, no special training is needed to use HCP101 etc. HCP101 was developed and tested during the SBIR Phase II grant period (# 5 R44 HL61994-03), for its applicability during in vitro and in vivo studies. Procedure for measurement of CO using HCP101 and the results from the studies conducted were presented to the FDA at a Pre-IDE meeting. FDA suggested specific safety and testing requirements for HCP101 at the Pre-IDE meeting before making the device commercially available. This formed the basis for this SBIR Phase II Continuation grant proposal and the objectives of this proposal are: (1) design the necessary hardware and software adjustments to implement the recommended safety features into HCP101;(2) conduct FDA recommended specific animal and human studies to test the robustness of the safety features incorporated and optimize the device features;(3) test the clinical ability of HCP101 to detect septal defects during animal and human studies;(4) validate HCP101 - CO measurements with those obtained from standard procedures (using perivascular probes/thermodilution method) and (5) finally proceed with the required IDE and 510(k) submissions. The above objectives will be achieved by studies at 2 animal and 5 human study sites - in different sub-groups to achieve a wide range of data encompassing several conditions and physiological variants. Standard testing including: biocompatibility, electrical safety tests etc. would be conducted for the complete HCP101 device and the extracorporeal AV disposable loop. PUBLIC HEALTH RELEVANCE Measurement of Cardiac Output is vital and is routinely done in adult population. There currently exists no technique to measure CO in about 30,000 (in USA per year) neonates (0.4-2.5Kg) and low weight pediatric (2.5Kg+) ICU patients due to small size vessels in these patients and procedural complexities. HCP101 will become the First Minimally Invasive System to measure CO in this vulnerable population.